The present invention relates to keyboard systems and more particularly is directed to an improved pushbutton keyboard system for use in electronic calculators to selectively close electrical circuits.
Keyboard systems, and particularly keyboard systems for electronic calculators such as shown in U.S. Pat. No. 3,725,907 which use metal staples as contact members have been very widely used. However, in using a system having staples as electrical contact members, there has been a problem of contamination of the contacts with particles, lint, solder flux and other air born dirt. Such contamination, which generally occurs during keyboard manufacture, can interfere with making of electrical connection to the contacts. There has also been some problem in proper spacing and alignment in using staples as the conductive contact members in a keyboard system. As a result, significantly high rejection rates have been experienced in making such keyboard systems.
Accordingly, it is an object of the present invention to provide an improved pushbutton keyboard system which is designed to minimize the effects of contaminates and to insure proper alignment of system components.
It is another object of the present invention to provide an improved pushbutton keyboard system in which actuation of individual push button members establishes positive electrical connections for transmitting electrical information.
It is yet a further object of the present invention to provide an improved pushbutton keyboard system which is relatively rugged and durable and which is extremely economical to fabricate on a mass production basis with very low rejection rates.